1. Field of the Invention
The present invention is directed generally to cargo loaders, and more particularly to cargo loaders for elongated objects, such as logs, that are transported on cargo container ships, railroad cars, trailers, and the like.
2. Description of the Related Art
In many countries, logs are harvested at a tree farm or in a forest and transported via a logging truck to a logging yard. At the logging yard, the logs are unloaded from the logging truck and stacked into large horizontal piles. Some of the logs are later sold to buyers who transport them via a logging truck to another logging yard or lumber mill.
Some logs are also purchased by buyers who transport the logs from the logging yard via a logging truck or railroad car to a cargo container ship located at a nearby port. The logs are then individually removed from the logging truck or railroad car and loaded onto piles located on the hull of the container ship. When the ship reaches its final destination, the logs are removed from the ship and re-loaded onto logging trucks or railroad cars, which subsequently deliver the logs to a logging yard or lumber mill.
Needless to say, loading and unloading individual logs on and off logging trucks or railroad cars and on and off the cargo container ship is dangerous and labor intensive. Also, when logs are placed in large piles on the ship, the logs can shift during transport causing the ship to lean to one side (or list) and potentially capsize. This problem may be avoided by loading logs into cargo containers that are stacked on the cargo ship but loading logs into an enclosed cargo container open only at its rear end portion is challenging. Presently, logs (and many other types of cargo) are loaded into containers one at a time. The loading process is typically done with the use of log handling equipment ill suited for the job.
The log handling equipment typically used is capable of picking up only one log out of a log storage stack and placing one end of that log into a container. Typically, the log must be re-grasped several times in order to push it fully into the container. Then, the next log is wrestled into the container. Because of the difficulties loading logs using prior art log handling equipment, employee safety is a significant concern. Further, the cargo container and/or other equipment may be damaged in the process.
When the container is finally full, the container truck operator must pull the load to a scaling device to determine whether the loaded container is under or over legal weight limits. If the container is too heavy or too light, logs must be removed from or added to the container. Then, the container must be re-weighed and the process repeated until the container has a satisfactory weight.
Therefore, a need exists for a method and apparatus for loading logs quickly and easily to and from a logging truck or railroad car and to and from a cargo container ship. In particular, a need exists for an apparatus configured to load logs and other cargo into a cargo container transportable on an over-the-road trailer, railroad car, container ship, and the like. The present application provides these and other advantages as will be apparent from the following detailed description and accompanying figures.